Razor blade strop and method of using the same



OGL 15, 1957 D. E. KEEcH 2,809,477

RAZOR BLADE STROP AND MTHOD OF USING THE SAME Filed June 25, 1956 1&6.c?. Maf. z2/16.6'.

IN VEN TOR.

United States atent This invention relates to the stropping of razorblades and has particular utility in stropping the edges of safety razorblades of wafer-like thinness.

it has long been known that the edge of a safety razor blade may bestropped by the simultaneous application to opposite faces of the bladeof stropping elements made of leather or rubber and then, while theblade is placed under pressure from said elements, withdrawing the bladefrom between said elements in a direction at right angles to said edge.in spite of this knowledge, how ever, an inexpensive and satisfactoryrazor blade strop operating on this general principle has not heretoforeeen provided.

lt is an object of this invention to provide a simple, inexpensive razorblade strop which can be manipulated manually in the manner aboveindicated to strop a razor blade and which will have a relatively highdegree of etiiciency in producing a keen shavinLT edge on said blade.

The razor blade strops of the general type mentioned and heretoforedeveloped have been based on tie princi le of applying pressure to theblade throughout its length simultaneously. l have discovered that whiletheoretically an advantage, this feature has two distinct disadvantages.lt causes the device to be unnecessarily large and by spreading thepressure applied thereto uniformly over the entire blade edge, it robsthe device of the capacity to apply a carefully adjusted and relativelyhigh degree of pressure to successive areas of the blade edge. have alsodiscovered that the application of such high opposing pressures to localareas of the blade edge is the secret of attaining uniformly goodstropping by this method.

it is therefore-another object ofthe present invention to provide afinger manipulated razor strop and method of using the same in which theblade is compressed between two stropping elements pressed thereagainstby the fingers to strop the blade edge, in which a relatively highVpressure may be applied in opposite directions to a small area oftheblade edge while withdrawing the blade from between the stroppingelements.

Another feature-common to strops of thisV general type produced in thepast has been the backing of the stropping element with metal plateswhich-greatly inhibits the dow of a rubber stropping element about themicroscopic metal particles of the blade edge when the blade is beingwithdrawn-from between the stropping elements.

it is an Vobject' of the present invention to provide a fingermanipulated razor blade strop and method of using the same in which thestropping elements are free to respond to the fleshy tips of the iingersand thumb, by which they are applied, so as to closely conform to thebeveled faces of the razor blade adjacent the edge particles to beVstropped whereby the material of the stropping elements will flow overthese bevelled faces, while said elements are pressed thereagainst witha relatively high local pressurepand the blade is being simultaneouslywithdrawn from between said elements.

lt is a still further object of t .e invention to provide rice a razorstrop including a pair of opposed stropping elements in which the wholestrop including said stropping elements and the means for connecting thesame and holding these resiliently in spaced relation ready to have thefingers applied thereto is comprised entirely in a single moldedarticle.

ln razor blade strops in the kprior art of the type being discussed thestropping elements were presented so as to cause occasional accidentalcollision of the razor blade edge with one of the stropping elementswhile the razor blade was being inserted edge rst between theseelements. Such collisions, of course, damage both the strop and therazor blade edge and seriously impair the utility of the strop.

It is another object of the present invention to provide a razor bladestrop of the general type mentioned which will render such accidentalcollision of the razor blade edge with the strop, while said blade isbeing inserted between the stropping elements, relatively easy to avoid.

The manner of accomplishing the foregoing objects as well as furtherobjects and advantages will be made manifest in the followingdescription taken in connection with the accompanying drawings in which:

Fig. 1 is a perspective view of a preferred embodiment of the invention.

Fig. 2 is an end elevational View of Vthe strop shown in Fig. l with thestrop held between the thumb and forefinger of one hand and showing howa single-edged razor blade may be inserted, edge first, between thestropping pads without likelihood of the cutting edge colliding with thestrop while the blade is being so inserted.

Fig. 3 is a View similar to Fig. 2 and shows the next step in applyingthe strop to the blade in which the stropping pads are pinched togetheruntil the extremities come in contact with the blade. This View alsoshows the steep convergence of the stropping pads as they are thusbrought into contact with the blade which feature also operates toprevent collision between the blade edge and the strop.

Fig. 4 is a View similar to Fig. 3 and illustrates the next successivestep in applying the strop to the razor blade. In this step thestropping pads are pinched to` gether on the blade so as to enfold theblade edge between the opposed stropping pads and apply substantialpressure from the thumb and forelinger through certain localized areasof said pads to the blade edge. This view also illustrates in brokenlines, the step of withdrawing the razor blade from between thestropping pads when the latter are thus pinched against the blade edge.

Fig. 5 is a face View of a single-edged razor blade and showing thestrop of the invention applied as in Fig. 4 to press the stropping padsthereof against opposite sides of a specific local area of the edgeportion of said blade at one end of the latter. This view also shows indotted lines how the entire edge of said blade may be stroppedbyapplication of the strop successively to similar like areasconsecutively located along the edge portion of the blade.

Fig. 6 is a face view of a double-edged razor blade showing a pair ofsaid strops applied thereto with corresponding local areas of therespective cutting edge portions of said blade gripped by theapplication of said strops thereto in similar manner to that'shown inFig. 4. This view also illustrates how similar consecutively relatedareas of the blade edge portions may be strapped by successiveapplications of the two strops to said blade.

Fig. 7 illustrates the manner of using the invention to strop adouble-edged bla-de and shows an end view of such a blade with a certainarea of one edge portion of said blade gripped by one of said strops andwith the blade manipulated, through the grip with which it isthus held,

Vedged blade.

to insert the opposite vedge portion of the blade between the stroppingpads of the second strop. Y

Fig. 8 is a view simila-r to Fig. 7 showing the completion of thelapplication of two strops in gripping relation with opposite localareasof the two edge portions of a double-edged blade. Y

Fig. 9 illustrates the next step inV stropping a double- This View showshow excessive pressure is applied in gripping one edge portion of saidblade withV one of said strops and a somewhat less pressure applied tothe opposite edge portion of the blade by the other strop, and the twostrops then pulled apart so as to slip the second strop away from itsgripping relation with the razor blade, thus stropping'that area of theedge portion of said blade which was gripped between the pads of thesecond strop.

Referring specifically to the drawings and particularly to Fig. l, theembodiment ofthe invention disclosed therein comprises an approximatelyU-shaped integrally molded soft rubber strop 10, including opposite sideelements 11 which comprise soft rubber stropping pads n flat sheet form,and an arcuate middle connecting element 12 lwhich is preferably of thesame thickness as the pads 11.

The inner faces 15 of the padsV 11 of the strop 10 are smooth land thestrop is preferably made of black carbon impregnated butyl rubberY withya hardness of 50 durometers. i

The strop of the invention may have any preferred external surfacecharacteristics but it isV highly preferable thatthe inner stropping padfaces be smooth. The strop 10 is adapted for stropping a sharpened edgeof a safety razor 'blade including the well known single-edged blade 16(Figs. 2-5) or the well known double-edged blade 17 (Figs. 6-9).

Reference will now be m-ade to Figs. 2 to 5 inclusive, which illustratethe various steps of the method of the present invention as this isperformed by applying strop 10 thereof in sharpening a single-edgedblade 16. Y The first step in performing this method is illustrated inFig. 2 where one of the strops 10V is shown as held lightly between thethumb and forefinger of one hand while a blade 16 is held by the metalshod4 edge Y18 thereof in the other h-and and the sharpened edgeportion' 19 of the blade, with cutting edge21 thereof in the lead, isinserted into the relatively wide U-shaped mouth of the strop 10. Thisview shows the latitude allowable in introducing the blade edge 21b'etween the stropping pads 11 of the strop 10 of theinventionrwithoutany collision being inadvertently produced between theA'blade edge and the rubber of the strop. Obviously, any such collisionwould be injurious to both the strop and the blader edge and must beavoided for the advantages of using the strop to be fully realized.

While holding the blade 16 with the sharpened edge portion 19 thereofinserted between the strop pads 11, the latter are pinched togetherbetween the thumb `and forenger, which results in these pads assuming anincreasingly steep convergence toward eachother and toward the razorblade, culminating in the free edges of the pads engaging the yblade asshown in Fig, 3. This manner in which the pads approach and recedefromthe blade prolikelihood of a collision between the razor. blade edge21 and the material of the strop. Y

Vvides an additional circumstance, tending to` prevent the Y The stepshownV in Fig.'3 is followed immediately by added pressure being appliedto the strop pads 11 from the thumb and foreiinger holding the stropwhich results in bringingthe pads 11 into parallel-clamping relationwith the edge portion 19 of theblade 16 `as shown in Fig. 4. Thisapplication of the strop 10 to the edgeportion 19 of the blade 16 ispreferably selected so that'the area 25 in which the pressure fromthethumb and foreiinger` is;Y

transmitted through the stropping pagdsll to the blade 16 A stroppingaction is now produced on that portion of the blade edge 21 lying withinarea 25 'by withdrawing the blade 16 from between the strop pads 11 inthe direction of arrow 26 at a right angle with the blade edge 21 whilemaintaining a substantial pressure on said blade edge portion in area 25thereof through said pads. Following this stropping of that part of theYrazor 'blade edge 21 ernbraced by area 25, the same stropping operationjust described for this area is repeated for similar areas 28 and 29which areas consecutively overlap each other and, taken together,embrace the entire. cutting edge 21 of the blade 16. Y

A fairly good stropping of the cutting edge 21 of the blade 16 may beaccomplished by covering the entire blade edge only once with a seriesof stropping operations as above described. A better stropping issometimes accomplished Iby going over the edge two or three times, butthis, of course is optional. Y

Reference is now made to Figs. 6, 7, 8 and 9 which illustrates the useof the stropV 10 for stropping the two cutting edges 35 and 36 of adouble edged blade 17. The

stropping of a double-edged blade 17 may be performed with a singlestrop 10 in Vexactly the same man-ner as above described for stroppingla single edged blade 16 in which case one edge portion 37 of the blade17 must be held in one hand while the other edge portion 38 of the bladeis being stropped. The blade is then reversed and the stropped edgeportion held in one hand while the unstropped edge portion of the Ibladeis stropped. This mode of operation, however, involves a danger ofgetting cut by gripping one'ed-ge of the blade with the hand. Likewise,gripping an edge portion -between the fingers in this manner, afterit'h'as been stropped, may impair the beneficial results -produced bystropping it. f

To avoid these difficulties in stropping a double-edged blade, themethod of the present invention preferably employs two of the strops 10in this operation. Fig. 6 shows two strops 10 applied to areas 39 and 40of opposite edge portions 37 and 38 respectively of the blade 17 towardone end of `said blade so as to snugly grip Vsaid blade edge portions insaid areas as shown in Fig. 8.

With the blade 17 gripped by said two strops, the pressure applied byone of the latter is increased above the pressure applied by the otherof said strops and the strops are then pulled apart as shown in Fig. 9,inthe directions of arrowsl 41 and Y42 thus; causing the blade to remaingripped by the strop through which the greater pressure is applied andpermitting the strop through which the lesser pressure is applied toslip from its clamping relation withv blade 17 at iight angles to edges35 and 36 thereof, thereby erecting a stropping action on that edgeportion of the blade lying. within the area which has been compressedbetween the stropping pads 11 ofV that strop. p

This operation is followed by allowing the strop 10, which was slippedfrom clamping relation with the blade, to expand as shown in Fig. '7 andthen reapplying thispto grip another area 43 of the same edge portion ofthe blade. An excessive pressure is now applied through that strop toarea 43 while a lesser pressure is applied to the area 39 by the stropon the other side of the blade, and the two strops are pulled apart.This will leave the blade gripped by pressure applied in area 43 whilethe blade edge embraced by the area 39 is stropped by the strop grippingthis being pulled from clamping relation with the blade.V

This second stropping operation on double-edged bladev 17, justdescribed, is followed by the reapplication of the left strop10 intogripping relation with the left bladeY cessive pressure being applied inthe area 44 and a lesser pressure in the area 43 and the two stropspulled apart to perform a stroppiug operation in the area 43. Followingthis operation the right hand strop is reapplied to the right edgeportion of the blade 17 to clamp the latter in the area 45. The blade isthen gripped with an excessive pressure in the latter area and with alesser pressure in area 44 and the two strops pulled apart stripping theleft hand strop from the area 44 and effecting a stropping action inthis area on the left blade edge 35.

The left hand strop 10 is now reapplied to the left blade edge portionto clamp the same in the area 46 with an excessive pressure and theright blade edge is clamped in area 45 with a lesser pressure while thestrops are pulled apart to effect a stropping operation in area 45. Theright hand strop 10 is now reapplied to grip the right edge of the blade17 with an excessive pressure in the area 45, and a lesser pressure isapplied through the other strop in the area 46 while the strops arepulled apart to effect a stropping operation in the area 46.

Both cutting edges 35 and 36 of double-edged blade 17 are now stroppedand the blade ready for use in shaving.

The drawings illustrate the invention at a scale so that when thedrawings are reduced in size in printing the patent, the patent willillustrate the invention correctly in full size scale.

It may be noted by observing the shape of the strop 1i) in Fig. 2, thatthis strop, when unconstrained, provides a mouth for receiving thecutting edge 21 of the razor blade 16 which is wide enough to permitconsiderable latitude in inserting said edge into said mouth withoutaccidentally contacting the strop 10 with said cutting edge. Dotted linerepresentations of the blade 16 in Fig. 2 illustrate this latitude. Thewidth of said mouth is considered to be the distance which the surfacesof the stropping pads 11 are separated at the free ends of said pads.The depth of said mouth may be considered to be the distance which theblade 16 would extend into said mouth past the plane of the free ends ofpads 11 if said blade were extended horizontally from the position inwhich it is shown in Fig. 2 until its edge 21 contacted the innermostpoint in said mouth. The length of said mouth may be considered as theoutside dimension of the strop 19 measured along the axis of curvatureof the middle element 12.

By reference to Figs. 2 or 7 it may be observed that, in the preferredembodiment of the invention here illustrated, the width of the U-shapedmouth formed by strop 1Q when the strop is free of constraint is almostas much as the depth of said mouth. Such a ratio between the width anddepth of the mouth of the strop 10 is highly desirable, although theinvention may be practically operated with a somewhat smaller ratiobetween the width and depth of said mouth. It is preferable, however,that the front opening of the mouth of the strop 19 have a width whichis in excess of one-half the depth of said mouth, in order to preventaccidental collision between the cutting edge 21 and one of the pads 11when inserting said edge between said pads.

lt is also to be noted in Fig. 2, that the inside radius of curvature ofthe middle element 12 is approximately onethird the depth of said mouth.This ratio is preferable and this radius should be in excess of at leastone-fourth the depth of said mouth. 1t is also preferable that the pads11 diverge from their points of union with said middle element when thestrop 16 is not under constraint.

Attention is also called to the fact that the preferred embodiment ofthe invention shown in the drawings has an over-all width in the pianeof the mouth opening thereof which is approximately equal to theover-all depth of the unit. While the strop of the invention isdescribed as preferably made of soft rubber, the claims employing thisterm are understood to also embrace equivalent materials.

Use of the strop 10 of the present invention as above described has beenfound to reduce the skin cuts otherwise suffered in safety razor shavingapproximately Such use also makes the razor cut the beard smoothly,closely and with practically no pulling, Its use furthermore doubles thenumber of shaves to be had from each blade as well as making all shavesuniformly excellent.

The claims are:

l. A method of strapping an edge of a safety razor blade which comprisesthe steps of interposing between the thumb and the forenger of one hand,a pair of soft sheet rubber pads, held in spaced relation and with saidpads free to resiliently adapt themselves to the shape of said thumb andforenger when said pads are forced together and compressed between saidthumb and forenger, inserting an edge portion of said safety razor bladebetween said spaced pads, pinching said pads and blade edge portionbetween said thumb and forenger to apply substantial compression to saidblade edge portion only in the area thereof corresponding to the opposedareas in which said pads are pressurally engaged respectively by thetips of said thumb and 'forefingen withdrawing said blade from betweensaid pads while so compressed, in a. direction at a right angle withsaid edge, and repeating said operation with successive fractions ofsaid blade edge portion disposed within the compression area aforesaid,whereby the entire blade edge is stropped.

2. A method as in claim l in which a double-edged safety razor blade isstropped and in which the aforesaid method is applied concurrently bythe respective thumbs and foreingers of two hands to the two edgeportions of said razor blade and in which said blade is held tightly bythe gripping of one edge portion thereof between one pair of said padsand thumb and forelinger of one hand, each time said stropping operationis performed on a fractional area of the other edge portion of saidrazor blade by the other hand.

3. A method as in claim 2 in which the successive fractional areastropping operations performed on one of the edges of said double-edgedblade are interspersed alternately between the corresponding successivefractional area stropping operations performed on the other of saidedges.

4. A safety razor blade strop comprising a pair of soft rubber stroppingpads in iiat sheet form and means for uniting said pads along one sideof said strop in widely spaced relation to form a relatively wideU-shaped mouth between said pads, the length of said mouth beingsubstantially shorter than said safety razor blade, said pads being freeto be pressed together between a thumb and a forelinger, while a razorblade extends between said pads, and to yieldably conform to the opposedtips of said thumb and forenger and transmit pressure to said razorblade confined substantially to the areas on said pads engaged by saidtips of said thumb and 'forefinger, a stropping operation taking placewhen a Arazor blade, thus compressed, is withdrawn from between saidpads in a direction at a right angle with the razor edge, a repetitionof said operation on successive fractions of said edge being requisiteto strop the entire edge.

5. A safety razor blade strop comprising an approximately U-shapedintegrally molded soft rubber unit in which the opposite side elementsof the U comprise stropping pads in flat sheet form and the middleconnecting element of the U comprises a torque-providing integratingbase which unites the stropping pads, and, when unconstrained, holdssaid pads in opposed spaced relation to provide a relatively wide mouthinto which a razor blade may be inserted, edge first, with relativelysmall likelihood of a frontal collision between said edge and saidstrop, said base yielding when said pads are pinched between a thumb andforeiinger to cause said pads to swing inwardly and converge at a steepangle in their initial contact with said razor blade, said pads thenyielding to further pressure 'from said thumb and forefor uniting saidpads along one side of said strop whereby the resiliency of the materialin said pads normally holds said pads, when unconstrained, in widelyspaced relation defining a wide mouth between said pads into which thesharpened edge of a razor blade may be readily inserted in Ya directionat right angles with said edge and Without colliding'with said pads,said pads being free to be di- Y rectly engaged respectively by thethumb and forelinger of a hand and to be liexed inwardly by saidengagement into compressing relation with said blade, said pads beingimmediately returned by said resiliency to said spaced relation upon therelaxing of pressure on said pads by said thumb and foreiinger.

7. A safety razor blade strop comprising a pair of soft rubberstropping'pads in at sheet form which are molded integrally with eachother so as to be thus united along one side of said strop and normallyheld by said integral relation, when unconstrained, in widely spacedrelation defining a wide mouth between said pads into which thesharpened edge of a razor blade may be readily inserted in a directionat right angles with said edge and without colliding with said pads,said pads being free to be directly engaged respectively by the thumband foreinger of a hand and to be exed by said engagement intocompressed relation with said blade, said pads being immediatelyreturned, by the resiliency of the material of which they are molded andby their integral connection, to said normal spaced relation upon therelaxing of pressure upon said pads by said thumb and foreiinger.

8. A combination as in claim 7 in which said strop comprises anapproximately U-shaped unit including a resilient sheet-form hingeelement, opposite extremities of which are integrally united with saidstropping pads, the wide mouth between said pads being substantiallyshorter than said razor edge, and having a front openn ing, the width ofwhich is in excess of one-half the depth of said mouth.

9. A combination as in claim 7 in which said strop comprises anapproximately U-shaped unit including a resilient sheet-form hingeelement, opposite extremities of which are integrally united with saidstropping pads, .the wide mouth between said pads, being substantiallyshorter than said razor edge, the inside radius of said hinge ele.

mentrbeing` in excess of one-quarter the depth of said mouth, saidYstropping pads diverging from their union with said hinge element, whennot under constraint, to

facilitate said introduction of said blade edge therebetween.

10. A combination as in claim 7 in which said strop comprises anapproximately U-shaped unit including a resilient sheet-form hingeelement, opposite extremities.

of which are integrally united with said stroppingvpads',

the Vwide mouth between said pads being substantially shorter than saidrazor edge, the width of said unit in the plane of said mouth openingbeing approximately equal to the depth of said unit.

11. A strop as defined in claim 7 which, when compressed between tips ofa thumb and foreiinger, with any portion of an edge of a double-edgedsafety razor blade held therebetween, transmits said compression fromsaid thumb and foreiinger to a maximum of approximately one-third ofsaid blade edge whereby, the withdrawal of said edge from between saidpads in a direction at right angles to said edge, while said portion ofsaid edge is thus compressed permits the stropping `of said one-third ofsaid edge with the full compressive capacity of said thumb and foreingerapplied solely to said one-third of said edge, said pads when releasedfrom pressure, immediately regaining their widely spaced relationwhereby a different and unstropped portion of said blade edge may beinserted rapidly in the opposite direction between said pads, forcontinuing the operation of progressively stropping said edge, afractional portion at atime.

References Citedlin the lile of this patent UNITED STATES PATENTS609,516 Mack Aug. 23, 1898 932,536 Conrad Aug.'31, 1909 1,179,459Kennedy Apr. 11, 1916 1,723,124 Bencze Aug. 6, 1929 2,629,211 TierneyFeb. 24, 1953

